Is it forever? Genotoxicological impact of marine contaminants on Arabian/Persian Gulf bivalves: An experimental approach

Abstract

A novel approach of combining manipulative field experiments and cytogenetic endpoints was used to assess the genotoxic impact of chemical contamination on a local model bivalve species, the pearl oyster -Pinctada imbricata radiata. Baseline levels of Polycyclic Aromatic Hydrocarbons (PAHs), Total Petroleum Hydrocarbons (TPHs) and trace metals were determined from surface sediments and pearl oyster tissue collected from 3 coastal locations in Qatar (Umm Bab, Dukhan and Al-Wakra). Initial aneuploidy –numerical chromosomal abnormality-level in oysters was also assessed during the baseline survey. The oysters’ ability to adapt to new sites, with distinct signatures in terms of chemical contamination, was assessed using a reciprocal transplantation experiment among the same 3 coastal locations, from February to April 2016. Significant differences in sediment contamination levels were detected among the 3 sites. TPHs were in higher concentrations at Umm Bab (western coast), while higher concentrations of metals and PAHs were found at Dukhan (western coast) and Al-Wakra (eastern coast), respectively. Oysters transplanted between locations showed lower levels of aneuploidy, relative to those kept in the original location (controls). Transplanted oysters, regardless of the contamination levels at the origin and destination, showed recovery from initial aneuploidy levels. Moreover, there was a larger percentage of aneuploid cells with chromosomal gain than with chromosomal loss in all treatments, which contrasts with the pattern usually observed in bivalves.